Guidance for Collecting and Preserving Soil and Sediment Samples for Laboratory Determination of Volatile Organic Compounds

FinalFebruary 28, 2006

The Department of Energy & Environmental Protection (DEEP) has issued a final guidance document on the above subject. This guidance document was prepared by DEEP with assistance from the DPH and EPOC. DEEP expects that all soil samples collected in, or for use in, Connecticut for the purpose of laboratory analysis for VOCs on or after March 1, 2006, the effective date of this guidance, be collected and preserved in accordance with the procedures described in this guidance document.

Background

Volatile organic compounds (VOCs) are lost from soil and sediment samples (hereinafter referred to as "soil samples") due to volatilization and biodegradation during collection, storage, and analysis. This leads to low-biased results. Some commonly used techniques are prone to relatively large losses and results that are potentially biased quite low. Such techniques involve collection of disturbed soil samples and storage in soil jars without air-tight seals. This guidance describes soil sample collection and preservation techniques designed to minimize such losses.

Statement of Purpose

Soil samples collected for laboratory determination of volatile organic compounds require special handling to prevent loss of VOCs that can lead to low-biased results. Historic sample collection procedures and associated handling of samples both in the field and in the laboratory may have lead to underestimation of VOC concentrations. This guidance provides environmental professionals with procedures designed to minimize losses of VOCs from soil samples. It is strongly encouraged that environmental professionals also read the background document entitled Rationale For Preservation of Soil and Sediment Samples for Determination of Volatile Organic Compounds (PDF) that was prepared by the Connecticut DEP QA/QC Workgroup.

Expectations Regarding Currently-Recommended Procedures and Use of Data Generated Using Other Procedures

DEEP expects that all soil samples collected in, or for use in, Connecticut for the purpose of laboratory analysis for VOCs on or after March 1, 2006, the effective date of this guidance, be collected and preserved in accordance with the procedures described in this guidance document.

DEEP anticipates that the vast majority of data generated before the effective date of this guidance (hereinafter referred to as "old data") will be acceptable without the need for resampling and analysis for VOCs. However, environmental professionals should evaluate the old data in the context of their site-specific conceptual model to determine whether potentially low-biased results for VOCs that may be present in soil at the site would create a significant data gap or whether the possible low bias might result in a potential significant risk to human health. Based on this evaluation, additional investigation and/or remediation may be warranted.